source: trunk/xgraph/jpgraph/Examples/windrose_2plots_ex1.php

<?php
require_once ('jpgraph/jpgraph.php');
require_once ('jpgraph/jpgraph_windrose.php');

// Data can be specified using both ordinal idex of axis as well
// as the direction label
$data = array(
    1 => array(10,10,13,7),
        2 => array(2,8,10),
        4 => array(1,12,22),
    );

$data2 = array(
    4 => array(12,8,2,3),
    2 => array(5,4,4,5,2),
    );

// Create a new small windrose graph
$graph = new WindroseGraph(660,400);
$graph->SetShadow();

$graph->title->Set('Two windrose plots in one graph');
$graph->title->SetFont(FF_ARIAL,FS_BOLD,14);
$graph->subtitle->Set('(Using Box() for each plot)');

$wp = new WindrosePlot($data);
$wp->SetType(WINDROSE_TYPE8);
$wp->SetSize(0.42);
$wp->SetPos(0.25,0.55);
$wp->SetBox();

$wp2 = new WindrosePlot($data2);
$wp2->SetType(WINDROSE_TYPE16);
$wp2->SetSize(0.42);
$wp2->SetPos(0.74,0.55);
$wp2->SetBox();
$wp2->SetRangeColors(array('green','yellow','red','brown'));

$graph->Add($wp);
$graph->Add($wp2);

$graph->Stroke();
?>